Eraser attachment for typewriters



NOV. 18, 1930. s CROSBY 1,782,060

ERASER ATTACHMENT FOR TYPEWRITERS Filed May 11, 1928 4 Sheets-Sheet 1 $.v9. C2406 by Nov. 18, 1930., s. A. CROSBY 1,732,060

ERAsER A'fTAcHMENT FOR 'TYPEWRITERS Filed M 11. 1928 4 sheetwsnmz 2 Nov. 18, 1930.

s. A. CROSBY 1,782,060

'RASER ATTACHMENT FOR TYPEWRBTERS Filed May 11, 1928 4 ,Sheets-Shqet 3 61:19. Grow by Nov. 18, I930.

ERASER ATTACHMENT ion TirP-EMzI'rERs Filed May 11, 1928 4 Sheets-Sheet 4 amma ltd? I 6'. A. C'raa bi flaw nay, wows. A.- CROSBY 1,732,060

Patented Nov. 18, 1930 PATENT: OFFICE STEPHEN A. CROSBY, OF PHILADELPHIA, PENNSYLVANIA V ERASER ATTACHMENT .FOB TYPEWRITEES Application filed. May 11, 1928. Serial H0. 276,934.

The object bf this invention is to provide a simple attachment for typewriters whereby .6 and operated to remove a an eraser will be supported upon the typewriter frame and automatically projected from the writtenpaper. Another object of the invention is to provide a device for the stated purpose in which the eraser will be out of the way of the type levers so that there will be no interference with the operation of the same in writing, and another object of the invention is to provide such an attachment which will be actuated bydepression of a key to be projected against the paper upon the platen of the typewriter and then rotated so as to remove the misprinted letter. The invention also provides means whereby the eraser will be automatically retracted upon release of the key, and further provides means for rotating the eraser when in contact with the paper and preventing rotation of the eraser until impact upon the paper has been effected. Other incidental objects of the invention will appear in the course of the following description, and the invention resides in certain novel features which will be particularly pointed out in the appended claims.

In the accompanying drawings which illustrate one embodiment of the invention,

Figure 1 is a front elevation of a typewriter having my attachment applied thereto, parts of the typewriter being omitted and so much of the same being shown as will afford an understanding of the invention;

Fig. 2 isa top plan view of the same, the eraser being shown at an intermediate point of its travel toward the platen;

Fig. 3 is an end elevation of the type writer with the invention applied thereto;

Fig. 4. is a top plan view of the attachment in the position of use;

Fig. 5 is a front elevation of the attachment on a somewhat larger scale;

Fig. 6 is a side elevation of the attachment with the parts in the position shown in Fig. 4;

Fig. 7 is a top plan view of the bracket which supports the working parts of the at-.

tachment;

Fig. 8 is a side elevation of thesame;

misprinted letter.

Fig. 9 is a front elevation thereof;

Fig. 10 is a rear elevation of the same;

Fig. IL is a longitudinal section of the housing which carries the eraser and the parts immediately cooperating therewith to effect rotation thereof, and i Fig. 12 is an end view of the same with the endplate of the housing removed.

In the accompanying drawings, the attachment has been shown applied to one standard make of typewriter and the supporting parts are designed with special reference tothat particular machine, but it is to be understood that the attachment is applicable to any standard typewriter and such minor changes in the design or the proportion of the parts as maybe necessary to conform to' the peculiarity of construction in any particular machine are within the scope of the invent-ion.

In the drawings, the reference numeral 1 indicates a portion of the frame of a standard typewriter, 2 designates the platen of the same, 3 designates the reels which carry the typewriter ribbon, and 4 designates the guide which centers the type faces as they print upon paper held to the platen. In carrying out the present invention, a verthe typewriter frame above and somewhat to .one side of the back spacer key 6 of the machine. A key lever 7 is pivoted at its rear end upon the rear corner post of the frame, as indicated at 8, and the front end of this lever projects through the slot 5 and is equipped with a key 9 corresponding in design to the usualkeys, indicated at 10. The ribbon reels 3 are carried upon brackets, indicated generally at 11, and these brackets in'the application of the present'invention are provided with forwardly projecting arms 12 and 13, the arm 12 being provided with an opening 14 in which is engaged the upper end of a spring 15 which has its lower end attached to the lever 7, as shown most clearly in Fig. 6, the lever being thereby maintained normally in its uppermost position. Extending vertically above and below the arm 12 is a guide post 16 having eyes or perforated lugs 17 projecting laterally from its upper and lower ends and slidably mounted through said lugs is a vertically disposed rack 18 which has its lower end forked to span the lever 7 and connected with the lever by a pin and slot connection 19, as shown in Figs. 3 and 6. This rack 18 meshes with a pinion 20 on the outer end of a shaft 21 which extends through and is jonrnaled in the ends of the arms 12 and 13, the inner end of said shaft having fixed thereto a second pinion 22 and a clutch disk 23, the clutch disk being of any approved construction, as will be understood. The forwardly projecting arm 13 and the main body of the bracket 11 are provided with inwardly projecting alined guide lugs 24 in which is mounted a horizontal rack 25 which meshes with the pinion 22 so that if the key lever 7 be depressed the rack 18 will be drawn downwardly and through the pinion 20 impart rotation to the shaft 21 which, in turn, will rotate the pinion 22 and thereupon cause the rack 25 to move forwardly in its guides. At the rear of the inner or rear guide lug 24, a short arm 26 projects from the bracket 11 at or near the top of the same and a pivot pin or bolt 27 extends through and is rotatable in said arm adjacent the outer end of the same. To the lower end of the pivot pin or bolt 27, a crank 28 is secured, and this crank is of an arcuate form, as shown most clearly in Fig. 4, the crank extending forwardly and laterally with respect to the pivot pin and having its free end, in turn,

'pivotally attached to the inner end of a pitman 29 which extends forwardly at the side of the rack 25 and at its front end carries a L pin 30 which passes through a longitudinal slot 31 provided in the rack 25 so that the rack may have some movement independent of the pitman and at the limit of such independent movement will actuate the pitman to exert a pull upon the crank 28 and thereby rotate the pin or bolt 27. Above the supporting arm 26 a swinging arm 32 is keyed or otherwise secured to the pivot pin so that the said arm will swing with the pivot and about the axis of the same as a center, and a housing 33 is carried by the outer end of said arm and preferably formed integral therewith, said housing constituting the support for the eraser and the parts acting directly thereon, as will be presently more fully set forth. A torsion spring 34 is coiled around the pivot 27 and has one end secured to a collar or cap 35 fixed to the upper end of the pin and its opposite end bearing against a pin or post 36 upon the arm 26. The spring thus tends to move the arm 32 and the housing carried thereby in a clockwise-direction so that it will be normally held in the position shown in Fig. 1 adjacent the front end of the arm 13.

The housing 33 is of such form as to define an upper sleeve or cylindrical member 37 ing parts within the housing may be readily assembled. J ournaled in the lower portion of the end plate 39 and in the opposite end wall of the housing is a drum or shaft 40 which has its end journaled in the end plate projected beyond the same and formed into a clutch member 41 mating with and adapted to engage the clutch member 23 in the normal position of the device which is illustrated in Fig. 1. A gear wheel 42 is secured upon the drum or shaft 40 adjacent the wider end of the housing and fixed to rotate with said gear is a ratchet 43, as shown. Pivotally mounted .upon the end plate 39 above the ratchet is a dog 44 which is held to the ratchet by a spring 45 secured in any convenient manner upon the side wall of the housing and bearing upon the free end of the dog, as shown clearly in Fig. 12. The dog is extended upwardly beyond its pivot 46 and defines an arm 47 which is curved over the axis of the sleeve 37 to receive and be engaged by a cone 48 on the end of the eraser shaft 49 which extends through the sleeve 37 and is journaled at its outer end in the end of said sleeve, the inner end of the shaft being equipped with a pinion 50 which meshes constantly with the gear 42 so as to be rotated thereby but is of less width than said gear so that it may slide along the gear. An expansion spring 51 is coiled around the eraser shaft 49 and bears at one end against a collar or other abutment 52 on said shaftand at its opposite end against a shoulder or wall 53' provided on the housing by cutting away a portion thereof, as indicated at 54. The spring 51 normally holds the eraser shaft projected, as shown in Fig. 11, but upon impact of the eraser against the platen or against a sheet of paper on the platen the force of the spring will be overcome and the shaft will be caused to slide toward the opposite end of the housing and the cone 48 will be thereupon projected under the'overhanging arm 47 of the dog 44 and will rock the dog so as to release it from the ratchet 43. To accommodate the point of the cone 48, an opening 55 is provided in the end plate 39, as will'he understood upon reference to Fig. 11. in assembling the parts. the abutment 5:2 may be a radially slotted disk engageable through the openings 54 in circumferential grooves in the eraser shaft.

A torsion spring 56 is wrapped around the drum 40 and is fixed at one end in the housing and at its opposite end in the gear 42 which is secured to said drum so that if the As a matter of convenience drum be rotated, as by depression of the key 9, the spring will be wound and will be held against unwinding by the ratchet 43 and the do 44. When the dog is released, however, as has just been described, the drum will be rotated by the unwinding of the spring and this rotation will be transmitted through the shown and described gearing to the eraser shaft 49 so that eraser at the end of the shaft will be rotated in contact with the paper and the misprinted character erased.

The eraser, of cylindrical form and removably fitted in a cap or other seat 58 on the end of the eraser shaft. When the eraser has been worn to such an extent as to be no longer satisfactorily useful, it may be easily removed and a fresh eraser inserted in the holder, and it is to be particularly understood that the particular form of the holder is immaterial as the eraser may be threaded into the same or may be held by an adhesive which will hold the eraser firmly through its use but will yield to slight force when a worn eraser is to be removed.

. It may also be noted that the tension of the spring 51 should be sufficient to normally hold the eraser shaft projected but yield readily to the impact of the eraser upon the typewriting paper.

The types of the typewriter all print at the same point of the platen and it is, therefore, desirable that the eraser may be caused to impinge point. To effect this result, it is intended a that the housing 33 enter the guide 4 when the eraser is brought into use, and in order that it may readily enter the guide and be held by and in the same, grooves or recesses 59 are formed in the opposite sides of the housing to be engaged by the arms of the guide in an obvious manner.

The eraser attachment, as will be understood from the foregoing description, is preferably mounted upon the bracket support for the ribbon-carrying reel, and this bracket has been re-designed or modified by adding to the usual bracket the several arms and guides which has been hereinbefore specifically mentioned. The bracket is secured in position in the usual manner by screws or bolts inserted through the attaching arm and it is provided with arms 61 for supporting and journaling the usual shaft and gearing for driving the ribbon reel.

The construction and arrangement of the several parts having been thus made known, it is thought the operation will be readily understood. Normally the parts are in the position shown in Fig. 1 with the clutch members 23 and 41 engaged and the spring 56 unwound so that there will be'no undue strain exerted on it. The key lever 7 is also held in raised position under the influence of the spring 15 while the pin 30 at the front end of the pitman 29 is at the forward end indicated at 57, is preferably against the platen at the same of the slot 31 in the rack 25. In the usual operation of a typewriter, when a key is depressed to print a letter, the platen moves one degree key is returned to its upper normal position, and in order that the platen may be moved backward to a corresponding extent the back spacing key 6 is provided. This back spacing key is, therefore, operated simultaneously with the key lever 7, when a misprinted letter is to be erased, so that the error will be returned to the printing point of the platen and the eraser will be centered to act'upon the misprint. The operator may depress the back spacer key by pressure of the little finger of the depress the key 9 by pressure from one of the other fingers. As the key lever 7 is thus swung downwardly, the rack 18'is drawn downwardly and effects rotation of the shaft 21, as has been stated. The rotation of the shaft 21 is transmitted directly to the drum 40 inasmuch as the clutch members 23 and 41 are engaged and the spring 56 is thereby wound. During the interval necessary for the winding of the spring, the rack 25 moves forwardly through its engagement with the pinion 22 and the slot 31 in said rack permits the latter to move past the pin 30 without imparting movement to the pitman 29. When the rear end of the slot 31, however, impinges upon the pin 30,- the pitman 29 Wlll follow the movement of the rack and, exert ing a pull upon the crank 28, will swing the arm 32 and the housing 33 at the free end thereof toward the platen, and the eraser will be thereby caused to impinge against the platen, as will be understood upon referepce to Figs. a 2 and 4. During this swinging movement of the arm 32 and the housing 33, the eraser shaft is in the position shown in Fig. 11 and rotation of the drum andthe shaft is prevented by ,the engagement of the dog 44 with the ratchet 43. jTheimpact of the eraser, howev r, against the platen or the paper thereon will overcome the tension of the spring 51 and the cone 48 will be thereby projected across the'dog to release the same from the ratchet and the eraser shaft will be rotated in the manner before described. The eraser will necessarily rotate with the shaft the misprint, the misprint will be erased. The eraser cannot at once rebound from the platen inasmuch as such movement is prevented by the engagement of the pin 30 with therear end of the slot 31, When the pressure upon the key 9, however, is removed, the sprin 15 at once contracts and returns the racks to their original normal positions and the spring 34 is then free toact so that the arm 32 and the housing 33 will be swung in the reverse direction to withdraw the eraser and engage the clutch 41 with the clutch 23, thereby setting the parts for another operaleft hand and at the same time.

and as it is now in contact with the paper at l tion. While a description of the operation appears to indicate that some considerable period of time is needed therefor, it must be understood that actually no more time is r quired to effect an erasure than is usually required to print a character. The slot in the I and the eraser swung to the platen and given with said gear for ample clearance.

sufficient rotation in contact with the paper to effect the erasure. U'ponrelease of the key 9, the springs 34 and 15 at once return the parts to the normal position. The attachment of all of the type bars and they may be operated without any thought of the attachment, the type bar nearest the attachment having The erasures are effected very quickly, two or three rotations of the eraser being ordinarily sufficient to remove the misprinted character and the action requires less time than is ordinarily consumed in hand erasing by expert operators. This saving of time effected by the use of my attachment is considerable in large establishments handling a large volume of correspondence or requiring large quantities of typing.

Having thus described the invention, I

. claim 1. An attachment for typewriters comprising an eraser shaft mounted for movement to and from an erasing position, an shaft, means ting said shaft, restraining said rotating means, the end of the shaft remote from the eraser being arranged to engage said restraining means, and means for moving the eraser shaft to and from erasing position, the shaft being end, wise movable restraining means and permit operation of said rotating means.

2. An attachment for typewriters comprising a slidably mounted eraser shaft, means for yieldably holding said shaft in projected position, an eraser carried by the projected end of the shaft, a pinion on the opposite end of meshing with said pinion, a spring connected rotating the same, means for normally restraining the" gear, said means being releasable upon endwise movement of the eraser shaft under impact upon material to be erased at the erasing position, and key controlled means for winding the, motor spring and moving the eraser shaft to and from erasing position.

the. shaft, a motor gear} 3. An attachment for typewriters comprisin a pivotally mounted arm, a drum rotata ly mounted at the free end of said arm, a gear fixed to said drum, a motor spring operable to rotate the drum and said gear, a ratchet fixed to the gear, a dog a adjacent said pinion, yieldable means holding the eraser shaft projected whereby upon impact at erasing position upon material to be erased, the eraser shaft will be retracted and the dog released spring, and key-controlled means for winding said spring and swinging the pivoted arm to carry the eraser shaft to and from erasing position.

'4. An attachment for typewriters tomprising a supporting bracket, a shaft rotatably mounted upon the bracket and having a clutch member at its inner end, an arm pivotally mounted upon the bracket, a drum carried by the free end of said arm and having a clutch member adapted to engage the first-mentioned clutch member, an eraser shaft mounted adjacent said drum and rotated thereby, a spring for rotating the drum and the eraser shaft, means for restraining rotation of the drum, the eraser shaft being endwise movable and constructed to release said restraining means, and key-controlled means for rotating the first-mentioned shaft to wind the motor spring-and then swing arm to erasing position to effect impact of the eraser shaft with material to be erased whereby to release said restraining means and permit rotation of said shaft.

tically movable rack in mesh with one of said pinions, a key lever connected with said rack to actuate the same, a horizontally movable rack meshing with the pinion near the ,inner end of the shaft, an arm pivotally :mounted upon the supporting bracket at the rear end thereof, a lost-motion connection between said arm and the horizontal rack, an eraser shaft carried by the free end of said arm, a spring actuated drum carried by said arm and geared to the eraser shaft, and a clutch member on said drum adapted to engage the first-mentioned clutch member whereby depression of the key lever will wind the spring of the motor drum to efshaft mounted upon sa1d bracket,a key lever -at one side of the bracket,"a vertically movable rack mounted upon the same side of the bracket and connectedjw'ith- 'saidflev'er, a-

pinion on the outer end of the shaft meshing with said rack, a horizontally inovablerack -mounted upon the inner side of ,the bracket,

said rack having a long1tudinalslot, a pinion adjacent the inner end of said-shaft meshing i to said arm a pitmanand extending forwardly beside the hori-' the free end of said vwith the last-mentioned rack,

the supporting bracket 7.

typewriter actuation of said motor when the arm 'is swung to the typewriter. platen and the eraser shaft set in erasing position, said-housing V an arm pivotally mounted upon at the rear e'ndof the same, a crankconnected pivoted to said crank zontal rack, a'pin carried by;

end of said, arm, a motor drum carriedby eraser .shaft,-and means whereby the rotation of the first mentionedshaftwill wind the p 7 motor drunn arm and geared to the means for moving the shaft and m'- l ments adapted .to couple the winding shaft i y 'to said rotating means, means for actuating the winding shaft whereby to 1 energize said L rotating means, be-

' lost-motion connections tween the winding shaft and the pivoted arm whereby to swing the arm and eraser shaft to erasing position after the rotating means is energized, means for restraining. said rotatingmeans, and means whereby to release restraining means upon impact of the eraser shaft at erasing position upon material to be-eraseds- I, the/from pend- I In testimony whereof Iaflix my signature. ofsaid pitman and' 11g glng in the slot in]; said rack,'an eraser shaft carrie'dbythe free A. GROSBY. [1,. 5.]

7 Thecombination with a typewriter having a platen and at'ypebar guide, of a pivotally mounted arm,

holding said armaway'from. the typewriter platenv and for swinging it'to the typewriter the'free end of'said arm, an eraser shaftmounted in said housing, ,a

platen, a housing at spring motor for'd'riving said shaft also mounted in said housing, 'means'for? winding said motor when the. arm is away platen, and means for effecting means for normally 1 from the having grooves in its sides adapted to engage the typebar guid'e'of the typewriter.

arm to carry-the eraser shaftfto and from an 1 erasing position, means on the armto rotate;

the shaft, means to normally restrain the ro tating means, and means on the shaft to release said restraining means when the shaft.

is moved endwise' by impact at erasing position with material to 'be erased.

9. An attachment vfor typewriters .com-

prising a slidably mounted i eraser shaft,

yieldable means for holding the shaft pro jected, an eraser on the'projected-end of the shaft, a motor geared to the opposite end of theshaft for rotating the same, a dog normally restraining the motor, an inclined surface on the shaft engageable with the dog to release the same when the shaft moves endwise upon impact of the eraser at erasin pos1t1on with material to. be erased, and 

